114 PRACTICAL BOTANY 



on the margin of which the stamens are borne, appears to 

 be grown fast to the ovary, the latter is said to be inferior ' 

 (Fig. 103). 



105. Floral diagrams. Lengthwise sections through the 

 flower greatly help the student to understand its structure. 

 But still more is to be learned from a suitable cross section. 

 Diagrams like those in Fig. 104 are constantly used in flower 

 descriptions to show the relations of the floral organs. Such 

 a diagram is not simply a sketch of the cut surfaces made by 



BCD 



Fig. 104. Floral diagrauis 



j-l, Lily family ; B, Heath family ; C, Madder family ; 73, Composite family. The 

 dot ahove the diagram indicates the position of the stem or axis which bears the 

 flowers. The sepals are distinguished from the petals by being represented with 

 midribs. In B the alternate stamens are printed lighter, since some flowers of 

 this family have five and some ten stamens. After Sachs 



dividuig the flower crosswise near its center ; it is rather a 

 representation of what would be shown if all the whorls of 

 the flower were brought into the best position for making a 

 characteristic section, which would pass through the middle 

 portions of sepals and petals and through the anthers of the 

 stamens and the ovaries of the carpels. Note that the sepals 

 are distinguished from the petals by being represented witli 

 midribs. If any part of the flower is lacking (as in the case 

 of antherless stamens, represented only by filaments), the 

 position of the missing or incomplete organ may be indicated 

 by a dot. 



1 Often flowers with superior, half-inferior, and inferior ovaries are said 

 to be respectively hypogynous, perigynous, and epigynous. 



